Fuse device and the like



Jan. 14, 1930. N. J. coNRAD FUSE DEVICE AND THE LIKE 4 Sheets-Sheet Filed April 11I 1925 Jae/mmf maw J'b/z/fac Jan. 14, 1930. N. .1. CONRAD FUSEv DEVICE AND THE LIKE Filed April 11. 1923 4 Sheets-Sheet www Jan. 14, 1930., N. J. CONRAD FUSE DEVICE AND THE LIKE Filed April 1l, 1923 4 Sheets-Shee 5 HEATER Jmmo /Y J Qn/md .Jario 14, 1930. N J, CONRAD l1,743,322

FUSE DEVICE AND THE LIKE Filed April 11, 1923 4 Smets-sheet A Imllllllmllllmllf MIIHIII JMe/zof Cafe/@d Patented Jan, 14, 1.930

NITEE) STATES PATENT' OFFICE NICHOLAS J'. CONRAD, OF WILMETTE, ILLINOIS, ASSIGNOR T0 SCHWEITZER & CONRAD, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS FUSE DEVICE AND THE LIKE Application led April 11,

My invention relates to fuse devices and the like and is concerned more particularly with fuse devices of the liquid containing type. 1

The chief object of my invention is t0 simplify and improve the construction and assembly thereof.

Another object is the provision of an improved process or method of sealing the ends of the tube 0r other enclosing member in the ferrule or terminals employed.

Another object is the provision of an im proved substance for sealing the ends of the tube and the vent cap in the errules.

A further object is the provision of an improved clip and mounting for the fuse and;

, in Figures A still further Object is the provision of an improved process or method of refilling or renewing the fuse.

In order to acquaint those skilled in the art with the manner of constructing and practicing my invention I shall now describe, in connection with the accompanying drawings certain speciic embodiments of the invention.

In the drawings:

Fig. 1 is a longitudinal section of a fuse embodying my invention;

Fig. 2 is a fragmentary longitudinal section-of the same after the fuse has blo-wn;

Fig. 3 is a transverse section taking on the line 3 3 of Figure 1;

Fig. 4 is a longitudinal section of the upper arcing terminals taken on the line 4-4 of Figure 1;

Fig. 5' is a top plan view 0f the lower internal terminal showing the manner of attaching the lowerend of the internal conducting cable or strand thereto.

Fig. 6 is a longitudinal section of the same.

Fig. 7 is a longitudinal section of a fuse of modified form.

Fig. 8 is a fragmentary longitudinal section of the same after the fuse has blown.

Fig. 9 is a top plan view of the fuse shown 7 and 8 with the vent cap removed.

Fig. 10 is a transverse section taken on the line 10-10 of Fig. 7.

Fig. 11 is a longitudinal section through 1923. Serial No. 631,263.

the upper arcing terminal taken on the line 11-11 of Fig. 7.

Fig. l2 isa side elevational view partially in section of the lower internal terminal.

Figs. 13 and 14 are longitudinal sections more or less diagrammatic showing the manner of sealing the ends of the tube in the ferrules.

Fig. 15 is a sectional view showing the step of preparing' the sealing substance.

Fig. 16 shows the step of drying and heating the assembled fuse in refilling or renewing the same.

Fig. 17 shows the step of preparing the fuse liquid preparatory to introducing the same into the fuse;

Fig. 18 is a side elevational view of the fuse mounting;

Fig. 19 is an enlarged front elevational view of one of the fuse clips;

Fig. Q() is a top plan view of the same, and

Fig. 2l is an enlarged fragmentary per` spective view of said clip, taken from one side thereof. l

The body of the fuse illustrated in Figures 1, 2, 3, 4, 5 and 6 is formed of a. sleeve or tube l of insulating material. While the particu- Ilar tube selected for illustration is cylindrical 1n form and is made of glass, it is to be understood that the particular formation may be a varied and the body 1 may be formed of fibre impregnated with bakelite or any other suitable or desired insulating material. Upon the ends of the sleeve or tube 1 are secured the metal ferrules 2 and 3 which form terminals for the conducting parts of the fuse contained within thesleeve 1.

The lower end or bottom of the lower ferrule 3 is closed as shown at 4. A boss 5 projects upwardly from the center of the closed end or bottom 4 and is bored and internally threaded to receive the threaded end 6 of a terminal member 7 secured upon the lower end of a flexible stranded conductor or cable 8 which extends through the body of the fuse and is connected at its upper end to the upper arcing terminals 9 and 10.

The terminal member 7 and the upper. arcing terminals 9 and 10 are formed of metallic sleeves or tubes. The lower end of the me- 3 tallc sleeve or tube forming the terminal member 7 is threaded as shown at 6- to be secured into the internally threaded boss 5 -of the ferrule 3 closing the bottom or lower end of the tube 1. The lower end of the strandedconductor 8 is inserted into theopen upper end of this terminal sleeve 7 and 'union be-l tween the sleeve 7 and strand 8 is then produced by deforming the upper end of the sleeve as by crushing or pressing it inwardly into substantiallythe shape o r configuration shown to compress the fibres of the stranded conductor and firmly and securely grip them in the terminal 'sleeve. The formation' of the upper end of the sleeve into substantially the shape shown permits engagement by a wrench or other suitable tool for the purpose of threading the lower end of the sleeve into the boss 5. In addition I lind that the union between the terminal member 7 and conductor 8 thereby formed provides an efficient, simple and inexpensive electrical and mechanical vconnection between the cable and the terminal.

The lower end of a coil tension spring 11 connected between the terminals 7 and 10, is bent diametrically with respect to the convolutions of the spring and is clamped between one of the upper flat faces of the terminal member 7 and a clip member 12 secured thereto as by means of a suitable screw 13 threaded through `the clip 12 and into 'a threaded openingformed through the upper end-of the terminal 7 in which the conductor' l8 is secured. The member 7 therefore in addition to electrically and mechanically connecting the lower ends of the conductor 8 to the ferrule 3 forms connection for the lower end ofthe operating spring-11. While the terminal 7. and clip 12 may both be grooyed if so desired I vfind that a groove 14 across the inner faceno'f the clip 12 provides suilicient retention for the lower end ofthe springll.

The upper end of the conductor or cable 8 is secured in a connecting member 15 which like the terminal l7 is lformed of a metallic sleeve into which the conductor is inserted andthe sleeve 15 and lvconductor then'con# nected or united by crushing or pressing the sleeve to distort the same and compress the libres of the conductor andfirmly :and securely grip them in the sleeve. The upper end of the spring-11 is bent diametrically like the lower end and is secured 'between the con- -necting sleeve l'and the lower arcing terminal 10, the sleeve 15 and terminal 10 beingclamped together by a suitable screw? 16 'and the inner lface of the terminal 10 being provided with'a groove 17 in which the upper end of the spring 11 is secured.'

The arcing terminals9 and 10 are formed of metallic sleeves into the adjacent ends of which the opposite ends of a fuse link 18 and strain wire 19 are inserted and opposite sides lof the sleeves forming these vterminals then crushed or pressed intol subtantially the formation shown in Figure 4 to securely grip them therein. A simple and effective mechanical and electrical connection is thereby provided between the fuse and strain links `18 and 19 and the arcing terminals 9 and 10.

Th adjacent ends of the terminals 9 and 10 employed to withstand such strain and normal-ly hold the parts" in set position. The wire 19 forms the mechanical connection and the fuse linkis rated' to vbreak the circuit at 'the desired point.

A liquid directingor Spraying member 22 is mounted upongthe'lower arcing terminal 10 b y means ofaf'suitable screw 23 the head of w ich screw is cbunteisunk into the member 22 as shown. This liquid directing or spraying member which is preferably made of lava, tends to direct or squirt liquid upon the place where the arc is drawn -Whenthe fuse blows. The liquid director 22 is in fact a plunger fitting more or less closely in the body of the fuse and having a central opening thelower end of which 'is preferably tapered or flared outwardlyv tov the lower end of the Y director as shown. l

The upper errule 2-isk provided with an interior flange 25. This interior. flange 25 forms an internal annular shoulder shown at 26 for the reception of a vent cap 27 provided for closing ofi` the upper ferrule'2 and a second annular shoulder shown at 28 for supporting aterminalfsupportingmember 29.y The terminal supportingfjmeinber 29 which is of generales-shaped formation and which is ico moror less resiliet'in order to secure good Contact with the sidewalls 25 ofthe ferrule 2, includes a substantially diametrically eX- tending intermediate portion 30 to which the upper end of theupper arcing terminal 9 is adapted to be secured as by means of a screw 32 whichvextends through an opening in the intermediate portion 30 of the supporting member 29-and through a registering opening 34 inthe upper ,end of the terminal 9 and l engages at its Kopposite end a suitable nut 35. "Iofacilitate setting of the fuse the terminal 9 is provided with an aperture 38 justbelow the aperture 34. Inv setting, the interior working parts are all properly connected between the lower terminal 7 and the upper arcing terminals. The lower end of the terminal member 7 is then threaded into the boss 5 projecting from the ferrule 3 and a tool having a hooked end is inserted into .the tube and engaged in the aperture 38. The terminal 9 is then drawn upwardly through the tube 1 against the tension of the spring 11 until the aperture 34 registers with the screw 32 in the intermediate portion 30 of the supporting member 29. Aperture 34 is hooked upon screw 32 which is previously threaded into cross member 30. A A nut 35 is then threaded upon screw 32 and it clamps the terj minal 9 to the cross piece 30.

lllhe sleeve or tube 1 is normally substantially filled with an arc extinguishing liquid which is introduced preferably through the open end of the ferrule 2 in a manner which will be hereinafter more fully described and the vent cap 27 quickly secured in place. The are extinguishing liquid employed is preferably a derivative of a suitable hydrocarbon. It may be any one of the liquids disclosed in Patent No. 1,319,907, dated October 28, 1919, or any preferred arc extinguishing liquid.

It is believed that the operation of the fuse will be apparent from the foregoing description. The non-conducting plug 21 conserves `and localizes the heat generated in the fusible wire 18 and when this wire is melted or fused, the strain or tension wire 19 is subjected to a heavy current. lt is immediately fused and the spring 11 draws the lower arcing terminal 10 down from the upper arcing terminal 9. The plunger or director 22 moving downwardly with the terminal 10 projects a stream ofthe are extinguishing liquid 40 upon the space where the arc tends to form.

Severe blowing tends to generate an excessive pressure in the container. The cap 27 provides relief by blowing off. This cap is sealed in place by a viscous non-hardening cement which provides a good seal and which provides a fairly uniform and definite mechanical bond.- This bond' tends to rupture at a fairly definite pressure, thereby preventing damage to the other parts of the container.

In the form shown in Figs. 7 to 12 inelusive the lower terminal member 50 comprises a pin or post the lower end of which is threaded as shown at 51 to be secured into the internally threaded boss 52 projecting upwardly from the center of the ferrule 53 closin olf the lower end of the body 54 of the fuse. rlhe upper end of the terminalv 50 which is bored out as shown at 55 is inserted through a block 56, the threads 51 being preferably formed suciently larger than the inserted end to retain the member 50 against displacement through the block `56 in one direction. rlhe lower end of the stranded conductor 57 is inserted in the upper bored out end of the terminal 50 and union between the strand and said member is then produced by crushing or pressing the wall of said member inwardly at opposite points to compress the fibres of the stranded conductor and firmly and securely grip them in the terminal member. As before a simple, eliicient and inexpensive mechanical and electrical connection is thereby provided. The fiat faces formed in the terminal member 50 permit engagement by a suitable tool for screwing the lower end of the terminal into the boss 52 and at the same time the swedging or crushing out of the upper end of the terminal forms retention shoulders for preventing displacement of the terminal 50 through block 56 in the opposite direction.

The screw 58 threaded through the block or collar 56 and into a threaded opening in the intermediate portion of the terminal 5() provides an additional securing means between the terminal 50 and collar 56 and prevents relative rotation therebetween. In addition the head of the screw 58 is splayed or flattened at'one side for cooperation with the spring 59 Aone of the lower convolutions of which extends between the head of the screw 58 and a pin 60 mounted in and projecting from the collar or block 56. A pin 61 projecting from the opposite side of the 'block 56 engages between two of the lower convolutions of the spring 59 and the spring is thereby connected to the block 56 in a simple and effective manner. One of the pins 61 is preferably positioned below the other as shown to permit threading of the lower convolution of the spring into cooperation therewith.

The upper end of the conductor 57 is se` cured in a movable terminal 65. The terminal 65 comprises a stem or post the-lower end of which is bored out as shown at 66 to receive the conductor 57 which is inserted therein. The terminal 65 is then crushed or pressed inwardly at opposite points into substantially the shape shown in the drawings thereby firmly and securely gripping the conductor in the bored out end of the terminal an'd effecting a simple, efficient and inexpensive electrical and mechanical connection therebetween. The upwardly extending shank 67 of the terminalmember 65 projects through a collar or block 68 mounted thereupon and secured against longitudinal movement and rotation relative thereto. Like the lower block 56 the block 68 is provided with a pair of off-set projecting pins 69 and 70 into cooperation with which the upper convolutions of the spring 59 are threaded and thereby secured. A screw 71 provides an additional securing means between the block 68 and terminal 65 and additional retention for the upper end of the spring 59.

The upper ferrule is provided with an internal flange 76 which flange 76 is formed with an annular shoulder 77 for the reception of thevent cap, 78, a second annular shoulder 79 and an outwardly flared or tapered surface 80. An annular ring 81 mounted in the ferrule upon the shoulder 79, supports a non-conductingA washer 82 through which the upwardly extending shank 67 of the arcing terminal 65 projects. The terminal 65 is held in place by a strain or tension wire 83 which passes through the shank 67 and is secured at each end under the heads ofl suitable screwsA S4 mounted at diametrically opposite points in the flared or tapered surface 80. The top or upper end of the shank 67 is provided with a lremovable screw 85'under which the intermediate p0rtion of a fuse link 86 is secured. The oppo` The upper terminal 65 is'guided by a plurality of fingers 92 formed of Wire and secured to the terminal 65. These fingers tend to prevent vibration of the movable system when the fuse is in operative condition. To obtain a simple, effective and inexpensive scheme of forming these fingers and securing them in place, I have devised the arrangement shown. One of the pairs of lingers 92 is formed of a single length of `wire which passes through an opening 93 in the shank of the terminal 65 and is then bent around the periphery of the shank 67, 90 degrees in the particular embodiment shown, and passed through an opening 94 at substantially right angles or normal to the opening 93. The other pair of fingers is formed of a similar length of wire passed through an opening 95,

bent around the periphery of the shank 67,

90 degrees and then passed through an open ing 96 -substantially normal to the opening- 95. This provides a simple, inexpensive Aand eiiicient scheme for securing the Wires, the pro]ecting ends of wlnchcooperate with the inside of the tube to guide the movable working parts of the fuse, and also to :damp anyg` vibrations of the spring and connected partei-"5y Otherwisesuch 'vibrations mi ht impose. de-

structive stresses upon Athe Wire y83.

JAs-inrthe embodiment illustrated ini-Fig-v` tires Lto" 6 inclusive, when the fuse link 86 is melted orifnsed, the ntension wire 83 is sub- V`jected' toaheavy current and to theA heat generated by the fusing ofthe link 86. It is fused at once and the spring 59 draws-the plunger downwardly, projectlng a stream of are extinguishing liquid 98 upon thespace wherevthe'arc tends toform.

fThefldillicultyfof properly sealing the ter-` minal flgrrules upon the opposite ends of thev tube has presented a considerable practical problem heretofore in the art.

To overcome this difficulty yI have devised an improved process or method of sealing the ends of the tube or enclosing member in the ferrules or terminals employed. In addition I have discovered a substance which is Abetter adapted or suited for this purpose'than anything .heretofore used. v I

According to this phase of my invention theV upper ferrule for example the ferrule 2 of the embodiment shown inlFig. 1 is arranged upon a sealing base 100 which sealing baseprojects upwardly from suitable heater 101 as shown in. Fig. 13. yA sleeve`102 preferably surrounds the sealing base v 100 and the ferrule 2 arranged thereupon, the sleeve 102 being preferablyY provided with a tapered or inclined upper edge which iaresiout from the upper edge of the ferrule2qfo`r a purpose which will be made apparent as this description proceeds. The glass tube'or sleeve 1 of the fuse which is first washed and dried in'a vacuum oven, is then inserted into the ferrule 2 with its lower edge resting uponthe taperednshoulder 103 therein.

A closure piece 104 is then arranged over the upper end of the tube 1 to close Voff the same. The closure element 104 is. provided with a suitable opening through whichv a suitable vacuum pump 105 is connected with the interior of the tube 1 by means of a tube 106 n and connection 107. The closure member 104 is made of or faced with such material as soft rubber, and so formed that it will effectively seal the upper end of the tube 1. The lower end 4of the ferrule 2 is sealed by cooperation with a suitable seat' 109 about-the sealing base 100. t Y

The ferrule 2 and tube 1 areheated by the heater 101 andthe substance employed for sealing the tube inthe ferrule is heated to the desired point in a suitable vessel 115 as shown in Fig. 15. This substance is then deposited,

as with a suitable knife 116 about the yupper edge of the annular space 110 between the tube and ferruleasshown at 111, the upper tapered 'edge of the sleeve 102 holding sulfi-l `cient quantity of the material to properly seal the .tube inplace. The pump is then operated'tolevacuatc the tube 1. The vacuum thus created in the tube 1 acts around the peredsurface 103`and up through the space and .draws the sealing substance 111 deylower-edgejof the tube resting upon the ta' the saine time' tends to properly center the tube in theferrule. Where the tube 1 is of glass as in'the embodiments shown the attendant has full vision of the space 110 from the inside and is therefore apprised when the vwhich leakage is possible.

Further difhculty has been encountered` heretofore with the substances employed forl mits leakage a ad materially increases the ratev of evaporation ot' the arc extinguishing liquid within the tube. Furthermore, the substance should be one that will not be attacked on one hand by the arc extinguishing liquid within the fuse or be permeable to the passage of the liquid therethrough on the other hand.

` cnd of said sleeve 2.

To overcome these deiests l have made a number of experiments to find a substance which is sui-ted for this purpose and tind that a suitably treated fusible phenol condensate such as is commonly sold under the. trade name of bakelite cement, or other substance having similar characteristics is better adapted for this purpose than anything used heretot'ore. It-provides the desired union between the tube and ferrule. It is in the nature of a non-drying cement which will not harden or become brittle. It is yieldablc and will not crack. It allows tor the different coellicients of expansion of the glass tube and metal ferrules -and will not be attacked by the arc eX- tinguishing liquid and is not permeable to the passage of the liquid therethrough.

After the fer-rule 2 has been sealed upon the tube or sleeve 1, said tube or sleeve is then provided with the errule 3. The ferrule 3 is loosely slipped over the end of the tube or sleeve 1 and the ferrule 3 is then set upon the block 100. This block is warmed by heater 101 upon which it rests. A split two piece collar 102 having a flaring or funnel shaped upper end is then secured upon the outside of terrule 3 with a shoulder 108 resting upon the top edge of ferrule 3 so as to provide a filling funnel or trough above the ferrule 3. T he upper end of the glass tube or sleeve 1 which bears the ferrule 2 cemented in place, connected to suction by the valve plug and gasket 104 resting upon the open The cemcntitious material is then drawn down into the space between the sleeve 1 and the inside surface of the ferrule 3, in the same manner as heretofore described. The split two-piece collar 102 is prevented from displacement bythe overhanging shoulder 108. Obviously, if desired, a solid collar like the collar 102 shown in Fig. 13 may be employed.

Another ditliculty has been in renewing or refilling blown fuses. Unless all of theenclosed parts are chemically clean and dry I find that a corrosive action is set up between the liquid and the fuse elements and the metal parts. This impairs the lite and functioning et the tusc.

To overcome this ditliculty my present invention embraces an improved method of renewing or refilling the fuse. According to this phrase ot" my invention the blown fuse upon being first carefully inspected is taken down, that is, the interior working parts, (spring, cable, terminals, liquid director, etc.) are all removed. The glass tube is then washed, thoroughly cleaned. and tested under air pressure to disclose any cracks or weak spots. The spring, cable and terminals are dipped in acid, Washed in a neutral bath and dried in a drying oven and the now thoroughly clean tube spring, cable, liquid director, terminals, etc. are reassembled with'a new fuse link or wire of the desired capacity.

The assembled fuse 120 is then placed in a vacuum oven 121 and gently heated. At the same time the fuse liquid, preferably a derivative of a suitable hydrocarbon, as already pointed out, is brought to the desired temperature, preferably about 50 C. in an electrically heated retort 122 sealed by a cover 123. The retort 122 is provided with vent 124. The vent 124 is provided with a calcium chloride and charcoal o r other suitable Elter 125 which absorbs allmois'ture and impurities from'the entering air. A suitable thermometer 126 may be arranged through the cover 123 and down into the retort 122 to apprise the attendant when the desired temperature is reached.

1When the temperature ot the fuse liquid reaches the desired point and the assembled fuse is thoroughly dried and heated to the desired point, the hot tube is removed from the vacuum oven and filled with the chemically pure and hot fuse liquid as by way of a tube 128. The vent cap 27 or 78 as the case may be with an application of the nondrying cement 111 provided for sealing the ends of the tube in the ierrules, about its upwardly flared flange 132 is then quickly pressed into place and the fuse hermetically sealed. The center ot the vent cap is preferably bulged slightly to permit proper springing of the cap into place. The hermetically sealed fuse is then placed in an oven for a heat test to disclose leaks, taken out and sub- `iected to a gas flame test, the presence of the slightest trace of fuse liquid around the joints being indicated by the color of the flame. The fuse is then butfed and cleaned and subjected to an electrical test after which it is ready for use.

The fuse mounting shown in Figs. 18, 19 and 20 comprises a pair ot post or supporting insulators 135 suitably mounted at their lower -ends upon a base 136. Terminal members 137 mounted upon the upper ends of the insulators 135 carry socket members 138 in which the line conductors are adapted to beI secured.

Spring Contact or'tuse clips 139 are mounted upon the terminal members 137. Each of the clips 139 is formed of a metallic strip bent to provide a suitable base, apertured as at 140 for mechanical and electrical connection portion and the opposite upperends 143 of the strip are curved downwardly to embrace the metallic terminals or ferrules 144 ofthe fuse 145 which is adapted for insertion therein.

Wire bails 146 are provided for clamping the ferrules 144 in the respective clips 139 and securely holding the same against' displacement. The opposite ends of these bails are bent inwardly into apertures in the upgements of a' suitable tool withjthe screws fuse into the positions shown, thejsides ,147,

of the clip being pressed or' sprungjqin taper-1` mit the bails to be swung' 'over-cand "embrace the same. The bail is relativelylleavy as compared with the thickness of the springzs'lip from which the clip is formed and the upper loopedv portions of the clip in particular are sprung together as shown to securely clamp the terminal of the fuse therein. Secure mechanical engagement and good contact is thereby maintained between the clip and the fuse terminals or ferrules mounted therein. A secure and effective mechanical and electrical engagement is thereby maintained between the inner ends of the clip and the fuse z terminals or ferrules mounted th`erein.

l the y.lails 146 have a doublefunction. They From the foregoing it will be apparent that cl p the clip into secure mechanical and good electricalengagement with the terminal of the fuse and by extending around the end of the fuse they serve in addition toi prevent accidental displacement of the fuse from the clip irrespective of the clamping effort exerted thereby. Lugs 175 struck up 4from the opposite side 147 x are adapted to limit the swing ofthe bails in one direction, lugs 175' being struck up to a less degree as shown in Fig. 21 and adapted for cooperation with the balls upon springing the same thereover to prevent accidental swinging o f -the bails in the opposite direction. The lugs 175 are formed to prevent accidental swinging of the bails 147 and at the same time permit springing of the bails past the same when it is def sired to release the fuse. When it is'desired to remove the fuse the clips are released by Vspringing the bails past the lugs 175 to the dotted line position 148 shown fragmentarily in Figure 20. I do not intend to be limited to the precise details shown and described, and I intend that -1.In afi1se of the character described, a

containing casing havinga pressure relief fopening, a fuse in the container, a liquid arc extinguishing material in the casing, and a removable cap covering said relief opening the casing, and being sealedy thereto by a` :viscous binder. i wardly extending sides 147 of the clip. 'lhese jf sides 147 normally flare outwardly as shown in dotted lines in Fi 19 thuspermitting easy insertion and with rawal' of the-fuse; Thev y. downturned ends of the clips 139 are recessed las shown at 190 to permit lconvenient en-j -V v"place'by a viscous binder. 141. When the fuse is inserted into' place thel bails 146 are swung up about the endsof 'the .,*QIn'a fuseof the class described, a containing casing having a pressure relief opening therein, a metallic ferrule forming a part ofthe casing about said opening, a fuse in the container, and a releasable metallic plug forthe opening, said plug being cemented in described, a fuse casing formed in partl of metal, said casing 3: In a device of the-class having a pressure relief opening through said ymetal part, a metal plug for 'said opening, anda viscous binder sealing said plug in the Opening- 4. In a fuse, the combination of a container formed in part of metal, an opening in said metal part, a fuse in the container having a portion thereof adjacent said opening, an arc extinguishing liquid in said casing, and a sheet metal cover for the opening, said sheet metal cover being cemented to the casing about the opening by a relatively non-drying cement and being adapted to be blown clear of the opening by excessive internal pressure.

ferule mounted thereon, said ferrule having a bore providing lan internal shoulder, a vent cap adapted for mounting upon said shoulder, said cap having a marginal flange extending along said bore, andbeing bulged to permit springing of said flange into said Mare.

, 7. A fuse comprising, anopen ferrul'ea cap ferrule and a cylindrical sleeve cemented into the ferrules, an are extinguishing liquidi therein, said open ferrule having a counterbore at its open end and a disc seated in said counterbore with a nonhardening cement formin a seal and a yielding mechanical binder between the disc andthe ferrule.

8. In combination, a container, a metallic ferrule mounted thereon,'a shoulder disposed within the ferrule, an S-shaped supporting member of resilient conducting material disterminal member supported by the intermediate portion of the supporting member.

' 9. In combination, a container, a conductor terminal member secured at one end of the "supportedrby the intermediate portion of the,

container, an arcing terminal member secured at the other end of the container, a second arcing terminal, a fuse link connecting the tivo arcing terminals, a second conductor terminal, means securing the second conductor terminal and the second arcing terminal together and forcing them toward each other,

a tension spring 'having 'one end clamped between said second conductor terminal and the second arcing terminal, means securing the other end of the spring to the first inentioned conductor terminal, and a flexible conductor secured at its ends to the respective conductor terminal members.

10. In combination, a container, a conductor terminal member secured at one end of the container7 an arcing terminal secured at the other end of the container, a second arcing terminal, a fuse link connecting the tivo arcing terminals, a second conductor terminal, means securing the second conductor terminal and the second arcing terminal together and forcing them toward each other, a tension spring having one end clamped between said second terminals, a clamping plate mounted on the first conductor terminal, means for forcing said plate toward the terminal, the other end of the spring being clamped between the plate and its associated terminal, and a flexible conductor secured at its ends to the respective conductor terminals.

11. In combination, a container, a metallic ferrule mounted thereon, an internal shoulder disposed Within said ferrule, an S-shaped supporting member of resilient conducting material disposed on edge with its arms seated upon Said Shoulder and urged laterally by ing spaced inwardly from the end ot the fertheir inherent resiliency into contact With the peripheral Wall of the ferrule, a terminal member supported by the intermediate portion of tlie supporting member, and means pulling on said terminal member to hold the supporting member edgewise in contact with the shoulder.

12, In combination, a container, a metallic ferrule'mounted thereon, an S-shap'edsupporting member of resilient conducting material seated on edge Within the f errule With its arms urged laterally by their inherent re` siliencv into close contact with the peripheral Wall olf the ferrulc, and a terminal member supporting member, the supporting member beingotherwise free from the errule.

13. In a fuse of the character described, a container, a metallic ferrule mounted thereon, a shoulder disposed Within the errule, a fuse connection Within the container and a support for one end of said fuse connection, said support comprising a member of conducting material and in the formv of an open figure and having an intermediate cross portion for attachment to the fuse connection and resilient arms'at its opposite ends seated upon said shoulder, said arms being other- Wise free of the ferrule and urged laterally by their inherent resiliency into contact with the peripheral Wall of the ferrule.

14. In a fuse of the character described, a container', a metallic ferrule mounted thereon, a shoulder disposed Within the ferrule, a fuse connection Within the container and a support for one end of said fuse connection, said support comprising a member of conducting material and in the form o an open ligure and having an intermediate cross portion for attachment to the fuse connection and resilient arms at its opposite ends seated upon said shoulder, said arms being otherwise free of vthe ferrule and urged laterallyv by their inherent resiliency into contact With the peripheral Wall of the errule, said support being spaced inwardly from the end of the ferrule and the internal diameter of the ferrul'e outwardly of said support being as large as the external diameter of the support to permit unobstructed removal of the support from the errule. l

15. In a fuse of the character described, a container, a metallic ferrule mounted thereon, a shoulder disposed Within the ferrule, a fuse connection Within the container, a support for one end of said fuse connection, said support comprising a member of conducting material and in the form of an open figure and having an intermediate cross portion for attachment to the fuse connection and resilient arms at its opposite ends seated upon said shoulder, said arms being otherwise free of the errule and urged laterally by their inherent resiliency into Contact with the peripheral Wall of the ferrule, said support berule and the internal diameter of the ferrule outwardly of said support being as large as the external diameter of the support to permit unobstructed removal of the support from the ferrule, and spring means associated with the fuse connection and yieldably holding said support upon said shoulder.

16. In a fuse of the character described, a container, a metallic ferrulemounted thereon, ashoulder disposed Within the ferrule, a fuse connection Within the container, a support forl one end of said fuse connection, said support comprising a member of conducting material and in the form of an'open, igure and having an intermediate cross portion for attachment to the fuse connection and resilient arms at its opposite ends seated upon said shoulder, said arms being otherwise free of the errulefand urged laterally by their inherent resiliency into contact with the peripheral Wall of the ferrule, said support being spaced inwardly from the end of the ferrule and the internal diameter of the ierrule outwardly of said support being as large as the external diameter of the support t permit unobstructed removal of the support from the errule, spring means associated with the fuse Connection and yieldably holding said support upon said shoulder, and

' a vent cap seated within the ferrule out- Wardly of said support and having amary ginal flange extending along and within the ferrule;

17. In combination, a closed container, av ferrule mounted thereon, said ferrule having a bore, a seat within thc ferrule, a vent cap adaptedlfor mounting upon said seat,

fitting said cap having a marginal flange extending l along and adapted to fit Within and'to exvso' tend along said borel and said cap being bulged to permit'springing said flange into said bore.

In witness whereof, I hereunto subscribe my name this 4th day of April, 1923.

NICHOLAS J. CONRAD.

nuages 

